DESpec: Spectroscopic upgrade of the Dark Energy Survey

Lead Research Organisation: University College London
Department Name: Physics and Astronomy


Dark Energy is one of the biggest mysteries in the whole of science. Observations over the past decade strongly favour a 'concordance' model in which the Universe is flat and contains approximately 4% ordinary atomic matter, 21% Cold Dark Matter and 75% Dark Energy. The Dark Energy paradigm and its extensions pose fundamental questions about the origins of the Universe: is Dark Energy an actual ingredient, or should Einstein's gravity theory be modified?

We propose a new initiative, the Dark Energy Spectrometer (DESpec), a 4000-fibre instrument for the Blanco 4-meter telescope in Chile that would take advantage of the infrastructure recently built for the Dark Energy Camera to achieve excellent science at low cost Starting in 2017, when the Dark Energy Survey (DES) is completed, DESpec would obtain spectroscopic redshifts for ~10 million galaxies from DES+VISTA Hemisphere Survey (VHS) and thereby improve our measurement of Dark Energy. DESpec will also constrain neutrino masses, enable new techniques such as redshift-space distortions to constrain Dark Energy vs. Modified Gravity models, and enable powerful studies of galaxy evolution. UK involvement would allow for the design to be harmonized with the needs and leadership roles of the UK astronomy community. As with DES, the UK investment would be highly leveraged by partnership with the US and other foreign partners. The total DESpec instrument cost is estimated at $40M, similar to DECam. The requested funding covers both instrumentation and and preparations for target selection and survey strategy. The work is fully coordinated with the work for BigBOSS:UK, another proposed spectroscopic instrument.

Planned Impact

The DESpec project will develop the skills of Post-docs and technical staff.

In particular, the work on simulations for target selection and survey strategy will be of use not only for DESpec, but also for a number of other planned spectroscopic surveys.

The Opto-Mechanical design and specification of the fibre imaging system will have broad implications for optical systems.


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Jouvel S (2014) Optimizing spectroscopic and photometric galaxy surveys: efficient target selection and survey strategy in Monthly Notices of the Royal Astronomical Society

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Kirk Donnacha (2015) Optimizing spectroscopic and photometric galaxy surveys: same-sky benefits for dark energy and modified gravity in Monthly Notices of the Royal Astronomical Society

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Levi Michael (2013) The DESI Experiment, a whitepaper for Snowmass 2013 in arXiv e-prints

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Newman J (2015) Spectroscopic needs for imaging dark energy experiments in Astroparticle Physics

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{Abdalla}, F. And {Annis}, J. And {Bacon}, D. And {Bridle}, S. And {Castander}, F. And {Colless}, M. And {DePoy}, D. And {Diehl}, H.~T. And {Eriksen}, M. And {Flaugher}, B. And {Frieman}, J. And {Gaztanaga}, E. And {Hogan}, C. And {Jouvel}, S. And {Kent}, S. And {Kirk}, D. And {Kron}, R. And {Kuhlmann}, S. And {Lahav}, O. And {Lawrence}, J. And {Lin}, H. And {Marriner}, J. And {Marshall}, J. And {Mohr}, J. And {Nichol}, R.~C. And {Sako}, M. And {Saunders}, W. And {Soares-Santos}, M. And {Thomas (2012) The Dark Energy Spectrometer (DESpec): A Multi-Fiber Spectroscopic Upgrade of the Dark Energy Camera and Survey for the Blanco Telescope in ArXiv e-prints

Title Hosting artists in residence 
Description We have hosted artists in residence who were inspired by Dark Energy studies 
Type Of Art Artwork 
Year Produced 2014 
Impact - Artist Katie Paterson (on Leverhulme grant; PI: Lahav) presented her work in museums around the world - Artist Marie Kaus produced art work on dark energy, on display at UCL Observatory at Mill Hill 
Description See the publications.

DESpec was merged with BigBOSS into DESI, in which several UK groups (including UCL) are participants.
DESI is now under construction, with expected observations in 2019.

the R&D work of DESpec was crucial towards building DESI, and ensuring UK leadership.
Exploitation Route Published in ArXiv (Green open access) and refereed journals

The results will and have been used to influence the future research carried out by ourselves and other astrophysicists.
Sectors Digital/Communication/Information Technologies (including Software),Education,Electronics

Description This grant is finished but this section can be updated at a later date if details required. - Media interviews and press release - Artist Katie Paterson (on Leverhulme grant; PI: Lahav) presented her work in museums around the world , and artist Marie Kaus produced art work on dark energy, on display at UCL Observatory at Mill Hill
Sector Education,Culture, Heritage, Museums and Collections
Impact Types Cultural

Description Advance ERC grant
Amount € 2,400,000 (EUR)
Funding ID FP7/291329 
Organisation European Research Council (ERC) 
Sector Public
Country Belgium
Start 05/2012 
End 04/2018
Title Optics and statistical methods 
Description - designing optical corrector for wide field multi object spectroscopy - developing statistics of cross correlations of imaging and spectroscopic surveys (Kirk et al.) - developing methods for selecting candidates of emission lines galaxies from imaging surveys 
Type Of Material Improvements to research infrastructure 
Year Produced 2014 
Provided To Others? Yes  
Impact See above 
Description press release and interview 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact a press release on DESI (which succeeded DESpec)
Interviewed in at article on DESI in Physics Today (Oct 2016)
Year(s) Of Engagement Activity 2014